Method for forging connecting rods



April 4, 1950 F. MELEY ET AL. 2,502,737

METHOD FOR FORGINGCONNECTING RODS Filed June 19, 1 45 I 5 Sheets-Sheet 1177 for/769- Aprifl 4, 1950 F. 'MELEY ET AL 2,592,737

METHOD FOR FORGING CONNECTING RODS Filed June 19, 1945 I Z5 Sheets-Sheet3 14%. or e a" Patented Apr. 4, 1950 UNITED STATES PATENT OFFICE METHODFOR FORGING CONNECTING RODS Application June 19, 1945, Serial No.600,377 In France November 2, 1944 1 Claim.

Our invention has for its object a method for manufacturing forgedconnecting bars having an integral fibre formation.

In accordance with said method we start from a blank having itself aproper fibrous constitution as obtained in accordance with the teachingsof the copending U. S. patent application Ser. No. 600,375, filed June19, 1945, for Method of forging blanks.

Operating according to said teachings, we obtain starting from a sectionof ingot or bar, two blanks wherein the less sound parts correspondingto the axial zone of the ingot 01' bar have been eliminated.

The method according to the present invention consists in plasticallydeforming the metal of these blanks in a manner such as will provide adirection and an arrangement of the fibres ensuring a maximum resistanceagainst stresses of opposite and alternating directions. In particularthis deformation provides for the fibres remaining perpendicular to thetransversal effort in the parts which resist to shearing stresses.

Appended drawing shows by way of example and by no means in a limitativemanner the application of our method to the manufacture of a masterconnecting rod for a seven-cylinder star motor.

Figs. 1 to 12 recall to mind the difierent known steps in the productionof a first blank having enclosing fibres without the impure portions ofthe original ingot section.

Figs. 1, 2, 4, 5, 7, 9 and 11 are side views and Figs. 3, 6, 8, and 12plan views, corresponding respectively to Figs. 2, 5, 7, 9 and 11.

Fig. 13 shows the blank in plan view after stamping.

Fig. 14 is a cross-section along line XIV-XIV of Fig. 13 of the sameblank.

Figs. 15 and 16 show the manner of performing a first and then a secondpunching.

Fig. 17 is a plan View of the blank after said punching.

Figs. 18 and 19 illustrate the manner of operating for a third and afourth punching operation.

Fig. 20 is a view of the blank when finished.

Fig. 21 is a cross-section along line XXIXXI of Fig. 2 showing the sameblank.

The original ingot section (Fig. 1), more or less forged or rolled,comprises impure parts in its axial portions as bonded by theinterrupted lines bcbc'. Its outer portions a. are on the contraryformed of sound metal. Starting from said ingot section, a first blankis prepared in accordance with the method disclosed in our saidcopending application. To this end it is given, through swaging, theshape of a shuttle as shown in Figs. 2 and 3. It is then flattened alongits axis so as to be transformed into a thick disc (Fig. 4). A furtherflattening in a direction perpendicular to the preceding gives the ingotsection the elongated shape shown in Figs. 5 and 6. It is swaged in amanner such that its ends become wider than the intermediate zone (Figs.'7 and 8). The central part mn-mn, in which the impurities are collectedis finally eliminated and one obtains two first identical blanksprovided with enclosing fibres. The principle of this manner ofoperating has been described in our copending above mentionedapplication.

A first preparation provides then the first desired blank containing noimpurities and having already a suitable fibre arrangement.

The stamped object assumes its final shape (Figs. 13 and 14). It is thenpunched to form the apertures in the head and foot of the corn nectingrod in two stages (Figs. 15, 16 and 17), then the axial holes for thefoot of the small connecting rod, also in two stages (Figs. 18 and 19)and the blank reaches thus its final state (Figs. 20 and 21) It isapparent that the fibres are disposed in parallel sheets with a singleout-- let at d. These fibres are perpendicular to the maximumtransversal stresses transmitted by the small connecting rods in theperipheric parts 6 of the head of the connecting rod in front of theholes serving for the pivotal mounting of the small connecting rods.

What we claim is:

A process for obtaining from an ingot preliminarily subjected to amechanical treatment to secure a longitudinal fibre structure twoconnecting rod blanks of sound metal wherein the fibres are parallel tothe contour of said blanks comprising attenuating the ends of said ingotby swaging to give it the form of a shuttle, flattening said shuttlealong its axis to form a thick disc, flattening said disc along adiameter thereof to form a bar with rounded ends, partially flatteningthe median portion of said bar and then removing the central unsoundpart of said flattened median portion of said bar to form said blanks.

FRANCOIS MELEY. ANDRE LEMOINE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 942,489 Dods Dec. 7, 19091,581,512 Coates Apr. 20, 1926 1,586,632 McConway June 1, 1926 1,707,778Witherow Apr. 2, 1929 1,791,187 Brauchler Feb. 3, 1931 2,080,640 TemplinMay 18, 1937 2,169,894 Griley Aug. 15, 1939

